1. Field of the Invention
This invention relates to an information management system that enables a user to manage an enterprise of the type requiring specified predetermined levels of human performance of tasks in a complex environment. In particular it relates to an information management system having improved capabilities for controlling a relational data base.
2. Description of the Prior Art
Managing complex enterprises involving complex environments, critical tasks, and complicated man-machine interfaces generally requires that a specified level of human performance of multiple, complex, often interrelated tasks be guaranteed. Optimum management implies that this be done at minimum cost. Examples of enterprises suitable for employment of the present invention include nuclear power plants, refineries, aircraft, banks, and insurance. As used herein, "enterprise" embraces the total activities regarding a project, from design through operation as regards human performance issues. The costs of an enterprise include:
(1) development of a requirements model for training, including task analysis, determination of criticality factors, and systems analysis; PA1 (2) specification and updating of man-machine interfaces; PA1 (3) development and maintenance of training curricula and materials, technical manuals, instruction books, and other job performance aids; PA1 (4) evaluation, training, and qualification of personnel; and PA1 (5) evaluation, updating, and maintaining of the enterprise itself in matters of human performance.
Large amounts of information are needed to develop and manage a complex enterprise. It is well known to store information in computer database systems. Relational databases are particularly useful in handling and correlating different categories of information. Modern relational databases include query languages, known as 4th generation languages (4GL), with which a user can use the computer system in an interactive mode that approximates the syntax of natural language. Standard query language (SQL) is an example.
Conventional relational database systems are based on tables (information entities). Each entity consists of related attributes in a predetermined format. An executing program extracts information from at least one, and generally more than one information entity table, and presents it in a coherent manner to the user. In order for the program to search for desired information in the entity tables, the tables must be related to one another by links, or relational keys, a process known as normalization. As is well known in the art, normalization theory is based on the observation that a certain set of relations has better properties in an updating environment than do other sets of relations containing the same data. Special linking tables are used when multiple instances of one entity are related to multiple instances of related entities, i.e. "many-to-many". As the number of related information entities in a database increases, the system of linking tables becomes complex and increasingly difficult to update and manage. These tables are static in a given state of the relational database, and require the intervention of a skilled database technician or administrator to modify. Incorrect adjustment of the linking tables could cause data to become inaccessible and the user could be misinformed. In the case of the enterprises contemplated by the present invention, there may be hundreds or thousands of different information entities, whose relationships to one another could be fluid during the development of the enterprise.
Vendors of relational databases provide utilities and tools for the generation of reports that contain information for the user. The development of such reports may require a coded program containing complicated statements in a syntax in accordance with the relational database definition, such as SQL statements. In the case of the information relating to the above-described enterprises, changes in the relational keys can affect the integrity of the report program. The tools known to the inventors for maintaining consistency in different aspects of the database are difficult to use.
Data entry constitutes a major limitation with standard relational databases. Most user interfaces are designed for transactional processing, an example being the depositing or withdrawing of funds at an automated banking machine. When the conventional transactional user interface is applied to applications which have data sets with large number of parameters, and where some of the parameters are blocks of discursive text, the efficiency of the data entry task can deteriorate to unacceptable levels.
Another shortcoming in conventional relational databases is the modeling of entity relationships. The processes affecting conventional entity relationships include sequencing, pointing, key inclusion, and querying. None of these can efficiently deal with tree structured hierarchal relationships, such as a high order binary tree.